Dimitrios Memmos

Use of phosphate-binding agents is associated with a lower risk of mortality

Hyperphosphatemia has been associated with higher mortality risk in CKD 5 patients receiving dialysis. Here, we determined the association between the use of single and combined phosphate-binding agents and survival in 6797 patients of the COSMOS study: a 3-year follow-up, multicenter, open-cohort, observational prospective study carried out in 227 dialysis centers from 20 European countries. Patient phosphate-binding agent prescriptions (time-varying) and the case-mix-adjusted facility percentage of phosphate-binding agent prescriptions (instrumental variable) were used as predictors of the relative all-cause and cardiovascular mortality using Cox proportional hazard regression models. Three different multivariate models that included up to 24 variables were used for adjustments. After multivariate analysis, patients prescribed phosphate-binding agents showed a 29 and 22% lower all-cause and cardiovascular mortality risk, respectively. The survival advantage of phosphate-binding agent prescription remained statistically significant after propensity score matching analysis. A decrease of 8% in the relative risk of mortality was found for every 10% increase in the case-mix-adjusted facility prescription of phosphate-binding agents. All single and combined therapies with phosphate-binding agents, except aluminum salts, showed a beneficial association with survival. The findings made in the present association study need to be confirmed by randomized controlled trials to prove the observed beneficial effect of phosphate-binding agents on mortality.

Fungal Peritonitis Complicating Peritoneal Dialysis during an 11-Year Period: Report of 46 Cases

The incidence of fungal peritonitis (FP) and the fungi that caused FP were evaluated in 422 patients treated with peritoneal dialysis. During an 11-year period, 804 episodes of peritonitis occurred, 46 (5.7%) of which were caused by fungi. Treatment was successful for 39 patients. Early diagnosis of FP and prompt therapy decreases morbidity and mortality.

Urinary levels of epidermal growth factor, interleukin-6 and monocyte chemoattractant protein-1 may act as predictor markers of renal function outcome in immunoglobulin A nephropathy.

Aim:  Urinary cytokine excretion may reflect histological changes in immunoglobulin A nephropathy (IgAN), and their measurement can give information about disease outcome.

COSMOS: the dialysis scenario of CKD–MBD in Europe

BACKGROUND Chronic kidney disease-mineral and bone disorders (CKD-MBD) are important complications of CKD5D patients that are associated with mortality. METHODS COSMOS is a multicentre, open cohort, prospective, observational 3-year study carried out in haemodialysis patients from 20 European countries during 2005-07. The present article describes the main characteristics of the European dialysis population, the current practice for the prevention, diagnosis and treatment of secondary hyperparathyroidism and the differences across different European regions. RESULTS The haemodialysis population in Europe is an aged population (mean age 64.8±14.2 years) with a high prevalence of diabetes (29.5%) and cardiovascular disease (76.0%), and 28.7% of patients have been on haemodialysis more than 5 years. Patients from the former Eastern countries are younger (59.3±14.3 versus 66.0±13.9), having a lower proportion of diabetics (24.1 versus 30.7%). There were relevant differences in the frequency of measurement of the main CKD-MBD biochemical parameters [Ca, P and parathyroid hormone (PTH)] and the Eastern countries showed a poorer control of these biochemical parameters (K/DOQI and K/DIGO targets). Overall, 48.0% of the haemodialysis patients received active vitamin D treatment. Calcitriol use doubled that of alfacalcidiol in the Mediterranean countries, whereas the opposite was found in the non-Mediterranean countries. The criteria followed to perform parathyroidectomy were different across Europe. In the Mediterranean countries, the level of serum PTH considered to perform parathyroidectomy was higher than in non-Mediterranean countries; as a result, in the latter, more parathyroidectomies were performed in the year previous to inclusion to COSMOS. CONCLUSIONS The COSMOS baseline results show important differences across Europe in the management of CKD-MBD.

Influence of Body Mass Index on the Association of Weight Changes with Mortality in Hemodialysis Patients

BACKGROUND AND OBJECTIVES A high body mass index (BMI) is associated with lower mortality in patients undergoing hemodialysis. Short-term weight gains and losses are also related to lower and higher mortality risk, respectively. The implications of weight gain or loss may, however, differ between obese individuals and their nonobese counterparts. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The Current Management of Secondary Hyperparathyroidism: A Multicenter Observational Study (COSMOS) is an observational study including 6797 European hemodialysis patients recruited between February 2005 and July 2007, with prospective data collection every 6 months for 3 years. Time-dependent Cox proportional hazard regressions assessed the effect of BMI and weight changes on mortality. Analyses were performed after patient stratification according to their starting BMI. RESULTS Among 6296 patients with complete data, 1643 died. At study entry, 42% of patients had a normal weight (BMI, 20-25 kg/m(2)), 11% were underweight, 31% were overweight, and 16% were obese (BMI ≥ 30 kg/m(2)). Weight loss or gain (<1% or >1% of body weight) was strongly associated with higher rates of mortality or survival, respectively. After stratification by BMI categories, this was true in nonobese categories and especially in underweight patients. In obese patients, however, the association between weight loss and mortality was attenuated (hazard ratio, 1.28 [95% confidence interval (CI), 0.74 to 2.14]), and no survival benefit of gaining weight was seen (hazard ratio, 0.98 [95% CI, 0.59 to 1.62]). CONCLUSIONS Assuming that these weight changes were unintentional, our study brings attention to rapid weight variations as a clinical sign of health monitoring in hemodialysis patients. In addition, a patients BMI modifies the strength of the association between weight changes with mortality.

Effects of vitamin E-coated membrane dialyser on markers of oxidative stress and inflammation in patients on chronic haemodialysis

BACKGROUND In the present prospective, controlled, observational cohort study, we investigated the effects of the use of a vitamin E-coated membrane dialyser (VEM) on markers of chronic inflammation, oxidative stress and endothelial cell apoptosis in end-stage renal disease (ESRD) patients on chronic haemodialysis (HD), as long as evidence of their effects on these pathogenetic routes are inconclusive as yet, despite their use for the last several years. METHODS Thirty-five stable ESRD patients underwent HD with the use of VEM for 6 months. Another 25 age- and sex-matched ESRD patients, being dialysed with conventional dialysers, served as controls. In both patient groups, beyond complete haematology and biochemistry work-up, serum CRP, apolipoproteins A1 and B, lipoprotein (a) (Lp(a)), hsIL-6, MCP-1, sICAM-1, sVCAM-1, sE-selectin, sFas and sFasL as well as plasma oxLDL, TBARS and TAS levels were determined at baseline and at 6 months of the study. RESULTS In the VEM group at 6 months, a significant reduction in CRP (P = 0.004), IL-6 (P = 0.004) and sICAM-1 (P = 0.04) levels was observed compared with baseline, along with a remarkable change in all markers of oxidative stress, i.e. increase in TAS (P = 0.005) and decrease in TBARS (P = 0.04) and oxLDL (P < 0.001). No significant changes were noted in the other parameters studied in the VEM group or in any parameter studied in the controls. Between the groups, significant differences were found in the change of CRP (P = 0.001), sICAM-1 (P = 0.03) and oxLDL (P = 0.04) compared with baseline. CONCLUSIONS HD with the use of VEM resulted in a significant reduction in inflammation and oxidative stress markers. Larger prospective randomized studies will need to confirm the findings of the present observational study.

Associations of fetuin-A and osteoprotegerin with arterial stiffness and early atherosclerosis in chronic hemodialysis patients

BackgroundCardiovascular morbidity and mortality remains excessive in patients with chronic kidney disease. The association of vascular changes with regulators of extraosseous calcification in this patient population is still under investigation. The aim of the present study was to investigate the associations of the calcification inhibitor fetuin-A, and the anti-osteoclastic factor osteoprotegerin (OPG) with vascular pathology in chronic hemodialysis patients.MethodsIn this cross-sectional study including 81 stable chronic hemodialysis patients, we measured carotid-to-femoral pulse wave velocity (cfPWV) with applanation tonometry, reflecting arterial stiffness, and common carotid intima-media thickness (ccIMT), a surrogate of early atherosclerosis, as well as serum levels of fetuin-A and OPG. Co-morbidities, traditional cardiovascular risk factors, inflammatory markers and mineral-bone disease serology parameters were also recorded.ResultscfPWV correlated inversely with fetuin-A (r=−0.355, p=0.001) and positively with OPG (r=0.584, p<0.001). In multilinear regression analysis including age, gender, diabetes, cardiovascular disease, hypertension, pulse pressure, LDL, logCRP, both fetuin-A and OPG were independently associated with cfPWV (p=0.024 and p=0.041 respectively). ccIMT was negatively associated with fetuin-A (r=−0.312, p=0.005) and positively with OPG (r=0.521, p<0.0001); however these associations lost statistical significance after adjustment for age.ConclusionIn chronic hemodialysis patients both fetuin-A and OPG levels are independently associated with arterial stiffness but not with early atherosclerotic vascular changes.

Carotid Atherosclerosis and Endothelial Cell Adhesion Molecules as Predictors of Long-Term Outcome in Chronic Hemodialysis Patients

Background/Aims: Cardiovascular disease (CVD) remains the leading cause of increased morbidity and mortality for hemodialysis (HD) patients. The aim of this study was to investigate the predictive values of carotid artery atherosclerotic lesions and endothelial adhesion molecule levels for long-term outcome in non-diabetic HD patients. Methods: 112 HD patients (60 male, mean age 59 years) consecutively entered the study. Atherosclerotic disease was assessed by measuring the mean and maximum intima-media thickness (IMT and IMTmax respectively) of the common carotid arteries using an ultrasound scanner. Circulating intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) levels were measured by ELISA. Patients were followed for the next 5 years and primary end points on follow-up were all-cause death, death from CVD causes and incidence of a CVD event. Results: Kaplan-Meier analysis showed that survival curves for all-cause mortality, CVD mortality and morbidity differed significantly between the upper and lower tertiles of baseline IMT (p = 0.002, p = 0.01 and p = 0.001 respectively) and IMTmax values (p = 0.0007, p = 0.006 and p = 0.0003 respectively), as well as ICAM-1 (p = 0.008, p = 0.003 and p = 0.02 respectively) and VCAM-1 levels (p = 0.004, p = 0.012 and p = 0.025 respectively). In non-adjusted analysis all-cause mortality and CVD mortality and morbidity were significantly associated with IMT (p = 0.003, p = 0.01 and p = 0.001 respectively) and IMTmax values (p = 0.001, p = 0.007 and p = 0.0007 respectively). After adjusting for other significant covariates, IMT values remained associated only with CVD morbidity (p = 0.03), while IMTmax were associated with both CVD mortality and morbidity (p = 0.03 and p = 0.01 respectively). All-cause mortality and CVD mortality and morbidity were also significantly associated with serum ICAM-1 (p = 0.004, p = 0.005 and p = 0.01 respectively) and VCAM-1 levels (p = 0.008, p = 0.02 and p = 0.03 respectively). After adjusting for the same covariates, the associations between ICAM-1 and all-cause mortality and CVD mortality and morbidity remained significant (p = 0.02, p = 0.01 and p = 0.02 respectively), while serum VCAM-1 levels were independently associated only with all-cause mortality (p = 0.02). Conclusions: In non-diabetic HD patients, carotid atherosclerosis and adhesion molecule levels are independent predictors of long-term clinical outcomes and may be useful surrogate markers for risk stratification in these patients.

FGF-23 Levels before and after Renal Transplantation

Phosphatonin fibroblast growth factor-23 (FGF-23) is involved in phosphate (P) excretion and vitamin D metabolism. Recently, FGF-23 has been suggested to be responsible for the hypophosphatemia and inappropriately low calcitriol levels observed after renal transplantation. We performed a prospective study to investigate FGF-23 levels in patients with end-stage renal disease before and after renal transplantation and their probable association with markers of bone and mineral metabolism. Intact FGF-23 levels were determined before and at 3, 6, and 12 months posttransplantation in 18 renal transplant recipients. Intact parathyroid hormone (iPTH), calcium (Ca), P, 25(OH)VitD, and 1,25(OH)2VitD levels were measured at the same time periods. Renal threshold phosphate concentration (TmPO4/GFR) was also calculated at 3, 6, and 12 months posttransplantation. The results showed that FGF-23 levels decreased by 89% 3 months posttransplantation (346 ± 146 versus 37 ± 9 pg/mL, P < .01) and remained stable throughout the study period. iPTH and P levels also decreased significantly after renal transplantation, while Ca and 1,25(OH)2VitD increased. Pretransplantation FGF-23 was significantly correlated with P levels at 3 months posttransplantation (P < .005). In conclusion, FGF-23 levels decrease dramatically after successful renal transplantation. Pre-transplantation FGF-23 correlate with P levels 3 months posttransplantation.

Impact of Long-Term Cinacalcet, Ibandronate or Teriparatide Therapy on Bone Mineral Density of Hemodialysis Patients: A Pilot Study

Background: Insufficient evidenced-based information is available for the treatment of osteoporosis in hemodialysis (HD) patients. Methods: In 102 HD patients, bone mineral density (BMD) was measured twice 16 ± 3 months apart. In the second BMD measurement 66 of them had a femoral neck (FN) T-score <–2.5. Of these 66 patients, 38 consented to a bone biopsy. Depending on both the bone biopsy findings and parathyroid hormone levels, patients were assigned to treatment groups. Eleven patients with osteitis fibrosa and iPTH >300 pg/ml received cinacalcet, 11 with osteitis fibrosa and iPTH <300 pg/ml received ibandronate, 9 with adynamic bone disease received teriparatide, and 7 with mild abnormalities received no treatment. A third BMD measurement was done after an average treatment period of 13–16 months. We compared the annual percent change of FN and lumbar spine (LS) BMD before and during treatment. Results: FN and LS BMD decreased significantly in the cinacalcet group, with an annual change of 3.6 and 3.4% before treatment to –4.2% (p = 0.04) and –7.7% (p = 0.02) during treatment, respectively. In the teriparatide group, FN and LS BMD increased, although not significantly, with an annual change of –5.4 and –2.6% before treatment to 2.7 and 4.9% during treatment, respectively. In both the ibandronate and the no treatment groups, BMD change rate remained negative during the whole study. Conclusions: Teriparatide administration improved BMD in HD patients with adynamic bone disease, although these results did not reach statistical significance. In HD patients with osteitis fibrosa, ibandronate did not improve BMD while cinacalcet reduced BMD.